Variable coil density anisotropic innersprings

ABSTRACT

Variable coil density anisotropic innersprings in which the placement and density of the coils or spring units varies between one or more regions or areas of the innerspring to provide innersprings with different average spring rates in different zones or regions of the innerspring. Various anisotropic arrangements of coils in innersprings are disclosed.

RELATED APPLICATIONS

There are no pending applications related to this application.

FIELD OF THE INVENTION

The present invention is in the general field of support structures andsystems and, more particularly, flexible support structures whichinclude springs.

BACKGROUND OF THE INVENTION

Spring systems for mattress and other reflexive support structures asused in furniture and seating typically have an array of interconnectedsprings or other recoil devices which support a reflexive supportsurface. Internal springs in mattresses (“innersprings”) commonly have aplurality of interconnected individual spring units in a matrix withparallel rows and columns. In one of the most common types of mattressinnersprings, which can be made by an automated wire-forming process,rows of helical wire springs or “coils” are produced and lined up forinsertion into an innerspring assembler which connects adjacent rows ofcoils by a lacing wire which runs between the rows transverse to alength of the innerspring. The spacing between the coils in each row isuniform, and can be set by adjustment of the innerspring assembler andheld in position by the lacing wire. Innersprings of different sizes aremade by changing the number of coils in each row and the total number ofrows. The coil density and resultant spring rate, supportcharacteristics and feel, such as stiffness and extent of recoil,however is uniform throughout the innerspring where the coils are evenlydistributed. Some innersprings also have a larger diameter border wirewhich is connected to the tops of the coils about a perimeter of theinnerspring.

Sleeping mattresses are constructed with a wide variety of materialsover and about the innerspring. Some of the materials are provided forenhancing the structural and reflexive properties of the innerspring,including support characteristics at the edges of the innerspring andmattress. For example, U.S. Pat. No. 5,787,532 discloses foam wallstructures which fit with the perimeter coils of a mattress innerspringto stiffen the edges of the mattress. Regardless of the amount ordifferent types of materials positioned about the innerspring or evenconnected to the innerspring, the homogeneous isotropic springproperties and support characteristics of the innerspring as a result ofthe even spacing and placement of the coils or spring units is notaltered.

SUMMARY OF THE INVENTION

The present disclosure is of anisotropic innersprings in which theplacement and density of the coils or spring units varies between one ormore regions or areas of the innerspring. As used herein, the terms“anisotropic” and “anisotropy” are used with reference to innerspringsin the physical meaning, i.e., having unequal physical properties indifferent areas or zones or regions or in different dimensions. In thecontext of innersprings, the anisotropy refers to the density of springsor coils and the consequent average spring rate and/or firmness ofdifferent regions of the innerspring resulting from the density andarrangement of coils in one or more regions of the innerspring, whichdiffers from the density and arrangement of coils and average springrate in other regions of the same innerspring. A region of ananisotropic innerspring of the disclosure is defined by groups of aplurality of coils which are positioned relatively at a common spacingor density. The spacing of the coils within the regions is differentfrom region to region, so that the coil density is different from regionto region. The padding and upholstery materials which are combined withthe innerspring to form a mattress may be selected and arrangedaccording to the density of coils of the region of the innerspring overwhich the materials are positioned.

Another aspect of the disclosure and invention is an anisotropicinnerspring with different numbers of coils in different regions of theinnerspring, the innerspring having a plurality of interconnected coilsarranged with axes of the coils parallel and ends of the coils locatedin common respective planes, the innerspring having multiple regionsdefined by groups of coils with axes of the coils spaced apart at acommon distance, including a first region with coil axes spaced at afirst distance and a second region with coil axes spaced at a seconddistance which is greater than the first distance; the coils of themultiple regions of the innerspring being interconnected by lacing wireswhich extend between the coils and from one region of the innerspring toanother region of the innerspring.

And a further general concept of the disclosure and invention is aninnerspring of the type which can be used in a mattress or otherflexible support system which has a plurality of interconnected coilsarranged with axes of the coils parallel and respective ends of thecoils in common planes which define opposed support planes of theinnerspring; a first group of coils arranged with axes of the coils ofthe first group spaced apart at a common first distance, the first groupof coils defining a first region of the innerspring; a second group ofcoils arranged with axes of the coils of the second group spaced apartat a common second distance which is greater than the second fixeddistance, the second group of coils defining a second region of theinnerspring, whereby a density of coils in the first region is greaterthan a density of coils in the second region, and a coil density of thefirst region is greater than a coil density of the second region.

These and other concepts and aspects of the disclosure and theinventions hereof are described in further detail in the followingDetailed Description made with reference to the accompanying Drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an embodiment of a variable coil densityanisotropic innerspring and an enlargement of an edge region thereof,and

FIG. 2 is an elevation view of a the variable coil density anisotropicinnerspring of FIG. 1, and

FIGS. 3-12 are plan views of alternate embodiments of variable coildensity anisotropic innersprings of the disclosure, each havingdifferent patterns, arrangements and zones of coils in the innersprings.

DETAILED DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS

As shown in the Figures, a variable coil density anisotropicinnerspring, indicated in its entirety at 10, is assembled with aplurality of springs or coils 20, shown as generally helical form coilswith first and second (or upper and lower) ends 21, 22 and a coil body23, which as illustrated is in the form of a helix which extends betweenthe coil ends. Other types and shapes of springs or coils may be used inaccordance with the principles of the disclosure, which is primarilyconcerned with the placement and relative placement of springs or coilswithin an innerspring, and is therefore not limited to any particulartype or shape of spring or coil. As used herein, the term “coil” meansand includes all forms of springs and coils which can be used in aninnerspring constructed according to the principles of the disclosure.

As shown in FIG. 1, the innerspring 10 is made up of a plurality ofcoils 20 arranged in a matrix or array, with coils generally aligned inrows R and columns C, with axes of the coils parallel, and respectiveends of the coils in common planes which define planar support or springsurfaces of the innerspring. The number of coils in each row and columnis dictated by the overall design size of the innerspring. Theinnerspring width W is generally determined by the number and spacing ofcoils in each row R. The innerspring length L is generally determined bythe number and spacing of coils in each column C. Although describedwith reference to width W and length L, such reference is forexplanatory purposes only and the relative anisotropic arrangement ofthe coils is not limited to the exact form shown.

FIG. 1 illustrates an exemplary variable coil density anisotropicinnerspring in which the columns C11-C13 and columns Cr1-Cr3, located atrespective longitudinal perimeters or perimeter regions of theinnerspring 10, are arranged at a lateral spacing between the columns(or between the axes of the coils) less than a lateral spacing betweenthe coils of the remaining columns C. Although illustrated in groupingsof he adjacent columns C11-C13 and Cr1-Cr3 which define the longitudinalperimeters or perimeter regions of the innerspring, the disclosureincludes other numbers or groupings of columns or rows with spacingsdifferent than, i.e. less than or greater than, other numbers or groupsof columns or rows of coils within an innerspring, which form groups orregions of coils which are distinct from other groups or regions ofcoils by the difference in relative spacing between the axes of thecoils within a group or region. For a mattress innerspring, the presentdisclosure provides coil anisotropy by greater coil density, as a resultof closer relative spacing between coil axes and columns, in thisexample along the longitudinal peripheral regions defined by columnsC11-C13 and columns Cr1-Cr3. This produces greater rigidity andstiffness along the longitudinal edge region of the mattress which isdesirable for increased edge support, anti-roll-off, and resistance topermanent set resulting from use of the longitudinal edge as a seatingsurface.

In conventional innersprings, the relative lateral spacing betweenhelical form coils in each row of coils, i.e., the lateral distancebetween the axes of two adjacent coils or between the outermost radii oftwo adjacent coils, is commonly measured and set with reference to thecoil pitch, which is the linear distance from one convolution of thecoil to an adjacent convolution, measured at the outer radius of thecoil convolutions and parallel to the longitudinal axis of the coil. Atypical uniform coil spacing in an innerspring may be, for example, twopitches, meaning that each coil is laterally spaced from adjacent coilsin a row at a distance of one to two times the coil pitch. The coilspacing thus set determines the coil density and overall spring rate ofthe innerspring. The coil spacing between adjacent rows of coils isgenerally very close, even to the point of being tangent or with someoverlap, as is necessary for the small diameter helical lacing wire towrap around the adjacent convolutions at the ends of the coils. Thus thelateral spacing of the coils in each row can be adjusted and varied inaccordance with the present disclosure, as for example by setting theinnerspring assembler spacing. One representative example of lateralspacing of coils in the rows, as shown in FIG. 1, is zero or tangentialspacing of the coils in columns C11-C31 and C1 r-C3 r, and one to twopitch or more spacing of the remaining coils in each row. The disclosureincludes any spacing or variable spacing of any coils or groups of coilsin a row, which spacing may or may not be repeated from row to row.

Other non-limiting examples and embodiments include closer coil spacingon one side or end of an innerspring; spacing which gradually orabruptly increases or decreases in the width or length directions of theinnerspring or in both the width and length directions; variable spacingwhich alternates, such as pairs or groups of coils which are closelyspaced or tangent with the pairs or groups separated by larger spacings;or different coil spacings from row to row, such as one row wherein thecoils are closely spaced or tangent, and another row wherein the coilsare at greater spacings. For automated assembly of innersprings of thedisclosure, any coil spacing which the innerspring assembler canestablish can be used to produce a variable coil density anisotropicinnerspring of the disclosure.

The variable coil density anisotropic innersprings of the disclosure canbe manufactured with the same total number of coils as in conventionalisotropic innersprings of the same overall size, e.g. twin, queen, king,because the conservation of coil spaces in the more dense regions isused in the less dense regions.

Another aspect of the innerspring designs of the disclosure, whereinthere are regions of the innerspring with differing coil density as aresult of variable lateral spacing in the coil rows R, is that eachregion by itself may be isotropic so that it provides uniform springeffect and support. The boundary of one region of lesser coil density bya region of greater coil density contributes to torsional rigidity ofthe innerspring as a whole, laterally or longitudinally. For example,the greater coil density of the regions defined by columns C11-C31 andC1 r-C3 r provided mechanical resistance to any tendency of theremaining central region to deflect or compress laterally from lateralor torsional forces on the coils of the central region.

Another aspect of the disclosure, and in particular an aspect of theanisotropic nature of the innersprings of the disclosure, is the gaugeof wire which is used to form the coils. The wire gauge may be variedaccording to the location and density (i.e., spacing) of the coils. Forexample, coils which are located in areas or regions of greater density,such as the coils in columns C11-C31 and C1 r-C3 r, may be made of wireof a different size gauge (smaller or larger) than the wire of the coilsin the remaining areas where the coil density is less. For example, thecoils of columns C11-C31 and C1 r-C3 r if made of heavier gauge wirewill produce an innerspring with even greater stiffness in the perimeterregions than if all of the coils of the innerspring are made of the samegauge wire. Related to this design variable is the size andconfiguration of the coils. For example, the coils located in regions ofgreater coil density may have a different (greater or smaller) diameterto the coil ends and/or the helical coil body than that of the coils inthe regions of lesser coil density. By varying these parameters, theoverall spring rates of the various regions of an innerspring can beformed to close specifications. Another non-limiting design example ofthis aspect of the disclosure is to form the coils located at theperimeter of the innerspring from relatively heavier gauge wire tofurther contribute to edge support and anti-roll-off characteristics.

FIG. 3 illustrates another embodiment of a variable coil densityanisotropic innerspring 10 in which coils 20 are arranged in columns Cin a repeating pattern of lateral spacing along the width W of theinnerspring. The longitudinal edges of the innerspring are formed by theclosely adjacent columns C11-C12 and Cr1-Cr2 to provide edge supportsimilar to that described with reference to FIG. 1. A centrallongitudinal region of the innerspring is defined by closely adjacent ortangential coils columns C1n and Crn. The central longitudinal region ofrelatively greater coil density and consequent spring rate can beenlarged by additional closely adjacent columns of coils. In the areasbetween the longitudinal peripheral regions and the central longitudinalregion the coil density and consequent spring rate is relatively less asa result of the increased lateral spacing of the columns Ci of coils 20.The density of the wire of the coils in columns Ci may be the same orgreater as that of the coils in the other columns. Also the overlyingmaterials which make up the mattress may be selected and arrangedaccording to the coil density of the underlying region of theinnerspring.

FIG. 4 illustrates a right/left version of an anisotropic variable coildensity innerspring 10 of the disclosure, wherein one lateral half orregion of the innerspring 10 has a greater density of coils 20 than theother. This type of innerspring is suitable for use in a his/hers typemattress constructed to have distinctly different supportcharacteristics and feel on each lateral half or portion thereof of thesleep surface. As illustrated, the spacing of the columns C1 of coils 20on the left lateral half or portion thereof of the innerspring may bestandard tangential or substantially tangential, and the spacing of thecolumns Cr of coils 20 on the right lateral half or portion thereofbeing relatively greater, resulting in lesser coil density and averagespring rate. For example, the spacing of coil columns Cr may be onepitch or more greater than the spacing of coil columns C1. In thisembodiment, the spacing or rows R is uniform along the length of theinnerspring, but does not necessarily have to be tangential orsubstantially tangential as shown, but rather with some degree ofspacing between the coils of the rows.

FIG. 5 illustrates a head/foot or upper body/lower body version of ananisotropic variable coil density innerspring 10 of the disclosure,wherein one upper or lower body region of the innerspring 10 has agreater density of coils 20 than the other. This type of innerspring issuitable for use in a mattress constructed to have distinctly differentsupport characteristics and feel on upper body or lower body regions ofthe sleep surface. As illustrated, the spacing of the rows Ru of coils20 in an upper region of the innerspring, for example oriented towardthe head of the mattress, may be tangentially or substantiallytangentially spaced, and the spacing of the rows R1 of coils 20 beingrelatively greater, resulting in lesser coil density and a lower averagespring rate over that region as compared to the region defined by coilrows Ru. For example, the spacing of coil columns Cr may be one pitch ormore greater than the spacing of coil columns C1. The relatively greaterspacing of the rows R1 of the coils results in a lesser number ofcolumns C1 than columns Cu, as illustrated by a ratio of 12:16, althoughother ratios are possible as related to the spacing of rows R1. In thisembodiment also, the longitudinal spacing or rows Ru and R1 is uniformalong the length of the innerspring, but does not necessarily have to betangential or substantially tangential as shown, but rather with somedegree of spacing between the coils of the rows Ru, R1.

FIG. 6 illustrates an additional alternate embodiment of an anisotropicvariable coil density innerspring of the disclosure wherein a centrallongitudinal region of the innerspring 10, defined by coil columns Ccwhich are spaced tangentially, provides an area of relatively greatercoil density and higher spring rate than that of the bi-lateral regionsdefined by coil columns C1. As with the other innerspringconfigurations, the overlying material which is used to construct amattress, and particularly the padding layers beneath the upholstery,can be selected and arranged according to the support characteristicsand spring rates of the underlying regions of the innerspring, such inthis case for example padding of greater density in the bi-lateralregions and/or additional layers to compensate for or work with thelower spring rate of the bi-lateral regions.

FIG. 7 illustrates an alternate embodiment of an anisotropic variablecoil density innerspring of the disclosure in which a pattern of coilspacing in each coil row is repeated, and the repeated pattern is out ofphase with the next adjacent coil row. For example, beginning with coilrow R1, from right to left, a pattern of three closely or tangentiallyspaced coils and three spaced apart coils is repeated throughout therow. In the next adjacent row R2, the same pattern is repeated, butbeginning at the right with three spaced apart coils. This alternatingshaft of the coil spacing pattern is then repeated. The coil densitythus varies within each row Rn, and from row to row throughout theentire innerspring.

FIG. 8 illustrates an alternate embodiment of an anisotropic variablecoil density innerspring 10 of the disclosure in which the spacing rowsR of coils of the innerspring gradually increases along the length ofthe innerspring, the spacing increasing either from the head end to thefoot end or vice versa. Though merely exemplary as shown, rows R1 and R2may be tangential or substantially tangential and repeated as such, orincreasing according to pitch, such as one pitch or one-half pitchincrease per row or greater. The gradation of the row spacing increasemay be linear or non-linear. The spacing of the rows R beyond tangentialresults in entire rows being devoid of coils. In order to lace the coilstogether, the lacing wires 21 are run longitudinally to interconnect thecoils which are adjacent or tangent in each row.

FIG. 9 illustrates an alternate embodiment of an anisotropic variablecoil density innerspring 10 of the disclosure in which the spacing inthe rows R and columns C is, with the exception of the end rows Re,non-tangential and preferably with a column intra-coil distance of oneor more pitches. The coil spacing in the rows R is at every other columnC. The coil spacing in the columns C is out of phase with the adjacentcolumns so that the coils of adjacent columns are not laterally aligned,with the exception of rows Re. Conversely, the coils of every othercolumn C are laterally aligned. This creates a desirable offset patternof distributed coil placement which is isotropic throughout a majorexpanse of the innerspring, and which can include greater density at theends, rows Re, and/or along the longitudinal sides. Also, althoughillustrated with the lacing wires 21 in a longitudinal orientation,conventional lateral lacing is also possible where the outer diametersof the laterally adjacent coils are generally aligned.

FIG. 10 illustrates one embodiment of a zoned type anisotropic variablecoil density innerspring 10 of the disclosure in which there aremultiple (e.g., three) zones or regions Ru, R1, Ru, of varying densitiesof coils 20 which are generally longitudinally arranged, for examplehead-to-foot, to form the anisotropic innerspring 10. One way in whichthe coil density of the zones or regions Ru, R1 can be made differentfrom other zones or regions is by varying the spacing of the columns C.As with other embodiments of the innerspring 10, the coil spacing withinthe columns C does not have to be the same in one region such as regionRu at the head of the innerspring, as in another region Ru at the footof the innerspring.

FIG. 11 illustrates an alternate embodiment of a zoned type anisotropicvariable coil density innerspring 10 of the disclosure in which theremultiple (e.g., five) zones or regions Ru, R1, of varying densities ofcoils 20 which are generally longitudinally arranged, for examplehead-to-foot to form the anisotropic innerspring 10. As with theembodiment of FIG. 10, one way in which the coil density of the zones orregions Ru, R1 can be made different from other zones or regions is byvarying the spacing of the columns C. As with the embodiment of FIG. 10,the coil spacing within the columns C does not have to be the same inone region such as region Ru at the head of the innerspring, as inanother region Ru at the foot of the innerspring.

FIG. 12 illustrates a further alternate embodiment of a zoned typeanisotropic variable coil density innerspring 10 of the disclosure inwhich there multiple (e.g., seven) zones or regions Ru, R1, of varyingdensities of coils 20 which are generally longitudinally arranged, forexample head-to-foot to form the anisotropic innerspring 10. As with theembodiment of FIGS. 10 and 11, one way in which the coil density of thezones or regions Ru, R1 can be made different from other zones orregions is by varying the spacing of the columns C. As with theembodiments of FIGS. 10 and 11, the coil spacing within the columns Cdoes not have to be the same in one region such as region Ru at the headof the innerspring, as in another region Ru at the foot of theinnerspring. The zones or regions of the embodiments of FIGS. 10-12 andthe other embodiments may be aligned or registered with overlying and/orunderlying layers of material which are positioned with the innerspringto form a mattress.

The foregoing descriptions are of representative embodiments of theprinciples and concepts of the disclosure which encompass and includeother types of anisotropic innersprings with variable coil densities.

1. An anisotropic variable coil density innerspring comprising aplurality of coils interconnected in an anisotropic array whereinrelative spacing between axes of the coils arranged in rows and columnsin the array is not constant throughout the innerspring, and lacingwires which extend between the coils to interconnect the coils in theanisotropic array and maintain the relative spacing between the axes ofthe coils.
 2. The innerspring of claim 1 wherein the coils in at leasttwo columns of coils of the array located at longitudinal perimeters ofthe innerspring are more closely spaced than other coils in the array.3. The innerspring of claim 1 wherein the spacing of coils in each rowof the coils of the innerspring is not constant and the spacing of coilsin each column of coils of the innerspring is constant.
 4. Theinnerspring of claim 1 wherein a density of coils in the longitudinalperimeter regions of the innerspring is greater than a density of coilsin other regions of the innerspring.
 5. The innerspring of claim 1wherein an average spring rate of the longitudinal perimeter regions isgreater than an average spring rate of other regions of the innerspring.6. An innerspring comprising: an anisotropic array of interconnectedcoils arranged in columns in rows with a common number of coils in eachcolumn and row; at least two columns of coils spaced apart at a firstdistance, and at least two other column of coils spaced at a seconddistance which is greater than the first distance; the coils beinginterconnected by lacing wires located between each row of coils andoriented transverse to the columns of coils.
 7. The innerspring of claim6 wherein perimeter longitudinal regions of the innerspring eachcomprise at least two columns of coils spaced apart at the firstdistance.
 8. The innerspring of claim 6 wherein a central longitudinalregion is comprised of at least two columns of coils spaced at the firstdistance, and columns of coils lateral to the central longitudinalregion are spaced from the central longitudinal region at the seconddistance.
 9. The innerspring of claim 6 wherein the lacing wires extendbetween columns of coils spaced at the first distance and columns ofcoils spaced at the second distance.
 10. An anisotropic innerspring withdifferent numbers of coils in different regions of the innerspring, theinnerspring comprising; a plurality of interconnected coils arrangedwith axes of the coils parallel and ends of the coils located in commonrespective planes, the innerspring having multiple regions defined bygroups of coils with axes of the coils spaced apart at a commondistance, including a first region with coil axes spaced at a firstdistance and a second region with coil axes spaced at a second distancewhich is greater than the first distance; the coils of the multipleregions of the innerspring being interconnected by lacing wires whichextend between the coils and from one region of the innerspring toanother region of the innerspring.
 11. The anisotropic innerspring ofclaim 10 wherein the plurality of interconnected coils are arranged incolumns and rows.
 12. The anisotropic innerspring of claim 11 whereinthe first region includes at least a portion of a perimeter of theinnerspring.
 13. The anisotropic innerspring of claim 10 wherein thefirst region includes at least two adjacent rows or columns of coils.14. The anisotropic innerspring of claim 10 wherein the second regionincludes at least two adjacent rows or columns of coils.
 15. Theanisotropic innerspring of claim 10 wherein the first region extendsalong a length of the innerspring.
 16. The anisotropic innerspring ofclaim 10 wherein rows of coils of the innerspring are spaced apart at aconstant distance in all regions of the innerspring.
 17. The anisotropicinnerspring of claim 10 wherein the lacing wires extend transverselybetween columns of coils and from one region of the innerspring toanother region of the innerspring.
 18. The anisotopic innerspring ofclaim 10 wherein columns of coils of the innerspring are spaced apart ata constant distance in all regions of the innerspring.
 19. Theanisotropic innerspring of claim 10 wherein a coil density in one regionof the innerspring is at least 25% greater than a coil density inanother region of the innerspring.
 20. The anisotropic innerspring ofclaim 10 wherein a region of the innerspring with a relatively greaterdensity of coils than another region includes at least a portion of aperimeter of the innerspring.
 21. The anisotropic innerspring of claim10 wherein a region of the innerspring with a relatively greater densityof coils than another region is at least partially located in a centralregion of the innerspring.
 22. An innerspring comprising: a plurality ofinterconnected coils arranged with axes of the coils parallel andrespective ends of the coils in common planes which define opposedsupport planes of the innerspring; a first group of coils arranged withaxes of the coils of the first group spaced apart at a common firstdistance, the first group of coils defining a first region of theinnerspring; a second group of coils arranged with axes of the coils ofthe second group spaced apart at a common second distance which isgreater than the common first distance, the second group of coilsdefining a second region of the innerspring, whereby a density of coilsin the first region is greater than a density of coils in the secondregion, and a coil density of the first region is greater than a coildensity of the second region.
 23. The innerspring of claim 22 whereinthe first region of the innerspring has a higher spring rate than thesecond region of the innerspring.
 24. The innerspring of claim 22wherein all of the coils of the innerspring are located in parallel rowswhich extend through the first region and through the second region. 25.The innerspring of claim 22 wherein all of the coils of the innerspringare located in parallel columns which extend through the first regionand through the second region.
 26. The innerspring of claim 22 whereinthe coils are arranged in columns and rows and wherein the coils arespaced at a common distance in each row of coils of the innerspring. 27.The innerspring of claim 22 wherein the coils are arranged in columnsand rows and wherein the coils are spaced at a common distance in eachcolumn of coils of the innerspring.
 28. The innerspring of claim 22wherein the coils are interconnected by lacing wires which extendbetween each row of coils and which extend from the first region to thesecond region of the innerspring.
 29. The innerspring of claim 22further comprising a third group of coils defining a third region of theinnerspring wherein axes of the coils in the third group are spaced at acommon third distance which is different from the spacing of coils inthe first region and different from the spacing of coils in the secondregion.
 30. The innerspring of claim 22 in a one-sided mattress.